The field of endeavor this invention is directed to a surgical instrument and a surgical knot tying aid, including but not limited to laparoscopic surgical knot tying.
This instrument and technique will be of immense value in laparoscopic or endoscopic surgery and any surgery requiring tying knots in suture in a deep cavity. Instrument placement often makes knot tying extremely difficult even for the most experienced laparoscopic surgeons. Inexperienced surgeons struggle with learning to knot tie with standard techniques so much so that procedures requiring suturing and knot tying are considered advanced procedures. In laparoscopic surgery instruments are placed into a body cavity filled with gas. The instruments are placed through devices called ports, which allow the instruments to be taken in an out of the body without loss of the insufflated gas. This gas fills the cavity providing room to manipulate instruments and visualize tissues. These ports allow limited movement of the instruments in the body because there is an effective fulcrum at the point in which the skin is breached. This restriction coupled with limited visualization in the body on a flat monitor makes tying knots inside the body (Intracorporeal) very difficult. Typically the smaller the angle between the two instruments being used to tie, the more difficult knot tying becomes. This difficulty is further exacerbated when the cavity in which the surgery is being performed is very small as is the case when placing sutures in the pelvis as would be done in a laparoscopic prostatectomy, or culpopexy. A growing trend in laparoscopic surgery is single port surgery. In single port surgery multiple trocars are placed through a single small skin incision. The advantage is a much better cosmetic result, as there is only one small incision. Natural orifice surgery is another trend in modern laparoscopic surgery that results in no visible skin incision. The drawback of these surgical approaches is that surgical instruments must be introduced into the body very close together. This further restricts a surgeon's ability to manipulate the instruments and therefore increases the difficulty of performing a surgery that would be more easily accomplished with a standard laparoscopic or open approach. This increased difficulty and decreased range of motion of the surgical instrumentation necessitates new instrumentation that can help accomplish surgical tasks under more restrictive conditions. One of the most difficult tasks is intracorporeal knot tying. The modified needle driver and complementary method of use, claimed in this patent application, make knot tying easy and allow for unrestricted port placement. This is of particular advantage in laparoscopic applications where instrument placement is limited, as it is in single port surgery and natural orifice surgery, and in situations where suturing is necessary in small spaces like in the pelvis. With the modified needle driver, a knot can be easily tied even with two instruments placed so close together that they are essentially parallel. This allows for surgery previously requiring open procedures due to the difficult knot tying situations to be performed laparoscopically. In the growing trend in laparoscopic surgery known as single port surgery this modified needle driver will allow the use of standard suture and ligature placement where suturing was previously impossible. This opens possibilities for new procedures to be done with the single-port approach that previously were not possible due to the need for knot-tying.
Standard endoscopic knot tying is accomplished after a stitch has been placed with an instrument called a needle driver. A surgeons knot is formed by multiple square knots tied in a succession of half hitches. Each half hitch is called a throw. A throw is formed with the use of two grasping instruments, typically a needle driver and a tissue grasper or second needle driver. A suture with a curved needle attached to at least one end of the suture is placed through the tissue to be tied using the needle driver in the right hand to manipulate the needle and place it in the desired position. If a ligature is to be placed then an angled grasper is often placed behind the tissue to be ligated and the suture handed with a needle driver to the jaws of the angled grasper and then the suture is pulled behind the tissue. In either case the suture is pulled through the tissue to leave a short suture end of approximately two and a half centimeters and a long end of eight to ten centimeters. The suture is now in a position to form a knot. The long suture is grasped with the instrument in the left hand and then with a difficult combination of moves the long suture is wrapped around the tip of the right hand instrument to form one or two loops around the end of the instrument. The right hand instrument with the loops around the tip must then be used to grasp the short end of the suture. This short end is then pulled through the loops surrounding the tip of the instrument and the ends are pulled in opposite directions to snug the first throw of the knot. The next throw is typically formed in the same manor only with the wraps wound around the right hand instrument in the opposite direction as the wraps in the first throw. Subsequent throws are done in an alternating fashion, which allows the knot to snug down flat forming a square knot, which is more secure. A standard surgeons knot starts with a throw that has two wraps around the instrument because this facilitates the knot holding snug once it is pulled tight on the first throw. Sometimes a slipknot is formed by making two throws in the same direction. This accomplishes the same thing as a surgeons knot, allowing the knot to be secured snugly before locking throws are applied. The rate limiting and most difficult step is wrapping the suture around the tip of the right hand instrument and then keeping the wraps on the tip while maneuvering the instrument into a position to grasp the short end of the suture. To make a double wrap to form a surgeons knot is often impossible however it is often preferable to the slipknot because the slipknot can fail to slip and not allow the suture to be tightened appropriately.
The lap needle driver is typically 14 inches long with a working end comprised of two jaws, which approximate to hold a needle or grasp suture. The large distance between the hand piece and the working end, the reliance on a two dimensional monitor and the restricted movement secondary to ports and port placement make intracorporeal knot tying very difficult.
Many attempts to solve the problem of intracorporeal knot tying have been made. Most are too complex, cumbersome or slow, if they even work at all. Task specific devices such as the endo-stitch have limited applications and are single use as well as expensive. Knot-pushers work but have many drawbacks, which keep them from being widely accepted. They require multiple instrument exchanges, which exposes the patient to increased risk of injury. They are slow to tie knots, and require very long sutures to be used, which are not available in all sizes. They increase the risk of tearing the suture out of delicate tissue. Intracorporeal knot tying aids are available but not widely accepted. Like the knot pusher they require multiple instrument exchanges with the added risk. Some advocate additional port sites for the tying aid. This also increases risk to, as well as scaring of the patient. Most surgeons prefer to minimize the number of port sites. Many other knot-tying devices have been patented but are not useful. The following examples illustrate the industry standard for laparoscopic needle drivers and the major differences between the modified needle driver, of claim one and some of the best attempts to improve laparoscopic needle drivers.
U.S. Pat. No. 5,242,458 held by Ethicon, Inc. (Somerville, N.J.) represents the industry standard laparoscopic needle driver. This is a typical design for most needle drivers in use today. It represents a standard jaw design with jaws that open approximately thirty degrees. This angle is not sufficient to control suture while knot tying nor is it designed to be.
U.S. Pat. No. 5,364,409 held by Ethicon, Inc. (Somerville, N.J.). This patent represents the basic laparoscopic needle driver employing a non-deployable shaft based accessory hook to capture suture and assist in tying. The key differences are that the hook is not deployable and retractable nor is it part of the jaw mechanism. This design for a non-deployable hook to aid in knot tying is not useful and is dangerous in practice because the hook would catch on tissue inadvertently. Knot tying with this configuration would be impeded because the hook is not retractable and would hinder the loops sliding off the instrument to form the knot. The hook for catching the suture would also catch on the seal in the trocar, impeding insertion and removal from the body cavity. This requires a second sleeve be employed to cover the hook to keep it from causing damage or impeding insertion and removal through the trocar. This requires added steps to knot tying and causes the instrument to have a wider shaft than the standard five millimeter.
U.S. Pat. No. 5,147,373 represents an attempt to ease knot tying by incorporating a second jaw into the shaft of a grasper or needle driver. This would allow for more control of the suture but the design is unnecessarily complex and would not be applicable to a standard five-millimeter diameter instrument. Other major disadvantages of this design include the necessity of a secondary control mechanism. This would slow the actual knot tying. The design claimed in claim one claims secondary control mechanism however the most useful example is the simplest with the jaw acting as the projection under direct control of the jaw mechanism. This allows the surgeon to focus on the task and not multiple controls. Claim one claims a radial projection to catch the suture as it slides over the shaft as it would be done in a standard knot tying procedure. This differs from any mechanism that would require actually grasping the suture with a secondary grasper of any design. The radial projection is an improvement over a secondary grasping mechanism because it does not require any extra steps be added to the knot tying procedure. The procedure using any secondary grasping mechanism would necessitate multiple added steps. The surgeon would have to release the jaw actuating mechanism, grasp the secondary mechanism, position suture in secondary jaw, grasp suture with secondary mechanism, move hand back to primary jaw mechanism, continue standard knot tying steps, then move hand back to secondary control, release secondary grasper, and finally finish remainder of standard knot tying steps. This is a lot of added complexity and time that is not necessary when using the claimed improved needle driver, which actually decreases the complexity of the knot tying procedure.
U.S. Pat. No. 5,601,578 Endoscopic suturing device 1997 United States Held by Miranic Investments Pty. Ltd. (Geelong, AU) This needle driver is similar in concept except the crucial difference is that the hook is not deployable and retractable. It would get in the way of manipulating the needle and tissue and could potentially be dangerous due to the ease in which tissue could be accidentally hooked and torn, especially while inserting or removing the instrument. The small diameter of the tip of the hook would also make inadvertent puncture of tissue a real and dangerous problem.
Tying knots through a single port approach with current technology is almost impossible. Intracorporeal knot tying is one of the most difficult techniques for laparoscopic surgeons to master and multiple inventions to simplify this difficult task have been designed. They all have one or more major drawbacks. Commonly, they necessitate exchanging instruments in and out of the access ports. This wastes time; increasing the time the patient must be under anesthesia and therefore increases the risk to the patient. Exchanging instruments also poses a risk to the patient by increasing the risk of accidental puncture or damage to other organs or structure during the exchange, as the visualization is difficult and instruments are not always visualized as they are exchanged. Risk of unintended and possibly unnoticed damage is increased with increased instrument exchanges. Another common drawback to knot tying devices is complexity. The more complex a mechanism the more likely it will malfunction. Surgical instrumentation must be reliable and durable. Single use mechanisms are not cost effective and complex mechanisms do not withstand the rigors of multiple washings and sterilization cycles. Many tying devices require set up for each suture or set up with device specific suture. This is once again time consuming and takes special training for surgeon and support staff. The majority of laparoscopic suturing and knot tying is still done with a traditional needle driver, which has not changed much in 40 years. Most surgeons want to tie the knot with the instrument they placed the suture with. They want the knot tying device to be versatile, and familiar. They do not want to have to learn complicated knot tying procedures or to use special suture that must be preloaded or set up for each stitch. Tying knots laparoscopically is difficult and learning how to do it takes a lot of time, practice, and aptitude. Not all laparoscopic surgeons master knot tying. The needle driver of claim one is simple, familiar and requires no new skill sets to be learned.